answer the following questions using the “world” database, available for download from OA 7.2. Present your SQL queries and/or processes that you used to derive the answers.

a. How many countries became independent in the twentieth century?

b. How many people in the world are expected to live for 75 years or more?

c. List the 10 most populated countries in the world with their population as percentage of the world population. [Hint: You can first find the population of the world and then use it for percentage for countries, so something like: select Population/5000000000 from Country ….]

d. List the top 10 countries with the highest population density. [Hint: For population density, you can try something like: select Population/SurfaceArea from Country where ….]